Method and arrangement in a wireless communication network

ABSTRACT

Method and arrangement in a first node for requesting a status report from a second node. The first node and the second node are both comprised within a wireless communication network. The status report comprises positive and/or negative acknowledgement of data sent from the first node, to be received by the second node. The first node comprises a first counter configured to count the number of transmitted Protocol Data Units, PDUs, and a second counter configured to count the number of transmitted data bytes. The method and arrangements comprises initialising the first and the second counter to zero, transmitting data to be received by the second node, comparing the value of the first and the second counters with a first threshold limit value and a second threshold limit value and requesting a status report from the second node if any of the threshold limit values is reached or exceeded.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/100,543 filed May 4, 2011, which is a continuation of U.S. patentapplication Ser. No. 12/350,619 filed Jan. 8, 2009 (U.S. Pat. No.7,948,879), which is a 371 of International Application No.PCT/SE2008/051139, filed on Oct. 7, 2008, which claims benefit of U.S.Patent Application No. 61/019,746, filed Jan. 8, 2008, the disclosuresof which are fully incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method and an arrangement in a firstnode comprised in a wireless communication network. In particular itrelates to a mechanism for Radio Link Control (RLC) polling forcontinuous transmission within the wireless communication network.

BACKGROUND

The transmission quality of a wireless communication and/or coherenceproperties of a communication channel between two nodes, such as e.g. abase station and a user equipment within a wireless communication systemmay differ, depending on a plurality of unwanted influence on the signaland the radio propagation conditions. Some non limiting examples of suchunwanted influence may be e.g. thermal noise and interference and someexamples of phenomena that adversely affect the propagation conditionsare path loss, signal multi-path, and Doppler spread. Further theaccuracy of channel estimation will affect the transmission quality.Thus data units such as e.g. a Protocol Data Unit (PDU) sent from onenode may arrive at the receiving node distorted or not at all. Inpractice RLC PDUs may be received out of order due to that different RLCPDUs are experiencing different number of Hybrid automaticrepeat-request (HARQ) retransmissions which may cause reordering.

It may then be necessary for the sending node to resend lost ordistorted data units to the receiving node. In order to perform aresending, the sending node in some way has to be informed which data,if any, to resend to the receiving node.

One mechanism that may be used in order for the sending node to know ifdata has to be resent is to poll the receiving node to send a statusreport back to the sending node.

The RLC protocol applied in an evolved UTRAN (E-UTRAN), also denotedLong Term Evolution (LTE), has been defined in the document 3GPP TS36.322 “Evolved Universal Terrestrial Radio Access (E-UTRA), Radio LinkControl (RLC) protocol specification Release 8” issued by the 3rdGeneration Partnership Project (3GPP). The RLC protocol includes apolling procedure that transmits polls according to a number ofcriteria. When a poll is triggered the RLC transmitter will set a pollbit in the RLC header, the poll bit serving as a request for a peerentity to send an RLC status report. Currently agreed criteria forsetting the poll bit are:

Firstly, transmission of last Protocol Data Unit (PDU) in a buffer, i.e.a poll is sent when the last PDU available for transmission orretransmission is transmitted.

Secondly, the expiry of a poll retransmission timer, i.e. a timer isstarted when a PDU containing the poll is sent and the PDU isretransmitted if the PDU with the poll bit is not acknowledged when thetimer expires.

Such criteria for setting poll bits may work well for bursty traffic,where the poll is sent for the last PDU in each burst. For continuoustransmission however, additional triggers may has to be considered. Aproperly designed polling procedure can be used to limit the number ofoutstanding, i.e. transmitted but not acknowledged, PDUs, or bytes, andto avoid stalling situations. Two mechanisms, counter-based andwindow-based, have been identified to avoid protocol stalling. Protocolstalling is an expression signifying that no more new data can betransmitted. Further, the polling mechanism may operate either ontransmitted RLC PDUs or on transmitted bytes.

A counter-based mechanism counts the amount of transmitted PDUs, orbytes, and sets the poll bit when a configured number of PDUs, or bytes,have been transmitted.

A window-based mechanism is similar but transmits the poll only when theamount of outstanding data exceeds a certain number of PDUs, or bytes. Awindow-based mechanism may need additional logic to transmit the pollregularly as long as the amount of outstanding data exceeds thethreshold.

However, none of the existing mechanisms does take into account thatstalling sometimes may occur due to sequence number limitations andsometimes due to memory limitations. In particular, the buffer memory ofa user equipment such as e.g. a mobile phone may be limited.

The user access quality and overall capacity in a wireless communicationnetwork environment is affected by data loss and protocol stalling, butalso by unnecessary polls and resending of data.

SUMMARY

It is therefore an object of the present invention to provide animproved wireless communication system.

According to a first aspect, the object is achieved by a method in afirst node for requesting a status report from a second node. The firstnode and the second node are comprised within a wireless communicationnetwork. The status report comprises positive and/or negativeacknowledgement of data sent from the first node to be received by thesecond node. When transmitting a sequence of data units or data unitsegments to be received by the second node, the first node counts thenumber of transmitted data units and the number of transmitted databytes. The first node then requests a status report from the secondnode, if the counted number of transmitted data units or the countednumber of transmitted data bytes exceeds or equals a predefinedrespective value.

According to a second aspect, the object is also achieved by anarrangement in a first node for requesting a status report from a secondnode. The first node and the second node are comprised within a wirelesscommunication network. The status report comprises positive and/ornegative acknowledgement of data sent from the first node to be receivedby the second node. The arrangement comprises a transmitter. Thetransmitter is adapted to transmit a sequence of data units or data unitsegments to be received by the second node. Further, the arrangementalso comprises a counting mechanism. The counting mechanism is adaptedto count the number of transmitted data units and the number oftransmitted data bytes. Further yet, the arrangement comprises arequesting unit. The requesting unit is adapted to request a statusreport from the second node if the counted number of transmitted dataunits or the counted number of transmitted data bytes exceeds or equalspredefined values.

Thanks to the present methods and arrangements, superfluous polling dueto both sequence number limitation and memory limitation is avoided byhelp of one single mechanism. By combining the two criteria “transmittednumber of data units” and “transmitted number of bytes” into onemechanism, it is avoided that a poll is unnecessarily sent when thefirst criterion is fulfilled in situation when such a poll has alreadyrecently been triggered due to the other, second criterion. Thusunnecessary signalling between the nodes comprised within the wirelesscommunication system is reduced, which leads to reduced overheadsignalling and thereby increased system capacity. Thus an improvedwireless communication system is provided as a consequence of thepresent improved mechanism for polling within the wireless communicationnetwork.

It is a further advantage of the present invention that the mechanismoperates on both bytes and data units and thus avoids stalling due toboth sequence number limitations and memory limitations. This isadvantageously achieved by a single mechanism coordinating the pollingby two criteria leading to an efficient polling mechanism.

An advantage of the present method and arrangement is that thegeneration of superfluous polls is eliminated or at least reduced.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described more in detail in relationto the enclosed drawings, in which:

FIG. 1 is a schematic block diagram illustrating embodiments of awireless communication network.

FIG. 2 is a combined signalling scheme and flow chart illustratingembodiments of a wireless communication network.

FIG. 3 is a flow chart illustrating embodiments of method steps in afirst node.

FIG. 4 is a block diagram illustrating embodiments of an arrangement ina first node.

DETAILED DESCRIPTION

The invention is defined as a method and an arrangement which may be putinto practice in the embodiments described below. This invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. It should be understood that there is no intent tolimit the present method or arrangement to any of the particular formsdisclosed, but on the contrary, the present method and arrangement is tocover all modifications, equivalents, and alternatives falling withinthe scope of the invention as defined by the claims.

FIG. 1 depicts a first node 110 communicating with at least one secondnode 120 in a wireless communication network 100. The communicationbetween the first node 110 and the second node 120 may be made e.g. overa communication carrier 140 in a cell 150 comprised in the wirelesscommunication network 100.

It will be appreciated that the number of components illustrated in FIG.1 is purely exemplary. Other configurations with more, fewer, or adifferent arrangement of components may be implemented. Moreover, insome embodiments, one or more components in FIG. 1 may perform one ormore of the tasks described as being performed by one or more othercomponents in FIG. 1.

The wireless communication network 100 may also comprise a control node130, according to some optional embodiments, depending on the technologyused. The control node 130 may be e.g. a Radio Network Controller (RNC).

The control node 130 is a governing element in the wirelesscommunication network 100, which may be responsible for the control ofbase stations e.g. the second node 120, which are connected to thecontrol node 130. The control node 130 may carry out radio resourcemanagement and some of the mobility management functions.

In some embodiments, the first node 110 may be represented by e.g. auser equipment, a wireless communication terminal, a mobile cellulartelephone, a Personal Communications Systems terminal, a PersonalDigital Assistant (PDA), a laptop, a computer or any other kind ofdevice capable of managing radio resources. A Personal CommunicationSystem terminal may combine a cellular radiotelephone with dataprocessing, facsimile and data communications capabilities. A PDA mayinclude a radiotelephone, a pager, an Internet/intranet access device, aweb browser, an organizer, calendars etc.

The first node 110 may however in some embodiments be represented by abase station, such as e.g. an access point, a Node B, an evolved Node B(eNode B) and/or a base transceiver station, Access Point Base Station,base station router, etc depending e.g. of the radio access technologyand terminology used.

The second node 120 may in some embodiments be referred to as e.g. abase station, an access point, a Node B, an evolved Node B (eNode B)and/or a base transceiver station, Access Point Base Station, basestation router, etc depending e.g. of the radio access technology andterminology used.

Further, according to some embodiments, the second node 120 may berepresented by a user equipment, a wireless communication terminal, amobile cellular telephone, a Personal Communications Systems terminal, aPersonal Digital Assistant (PDA), a laptop, a computer or any other kindof device capable of managing radio resources.

However, in the non limiting example depicted in FIG. 1, the first node110 is a mobile cellular telephone and the second node 120 is a basestation.

The wireless communication network 100 may be based on technologies suchas e.g. E-UTRAN, LTE, Code division multiple access (CDMA), WidebandCode Division Multiple Access (WCDMA), CDMA 2000, High Speed DownlinkPacket Data Access (HSDPA), High Speed Uplink Packet Data Access(HSUPA), High Data Rate (HDR), TD-SCDMA, Wimax, etc.

As a non limiting example only, and for purely illustrative purpose thisdescription is written with the invention embodied in an E-UTRANenvironment. However, the present method and arrangement may be usedalso in other technology environments.

FIG. 2 is a combined signalling and flowchart that depicts method stepsand the transmission of signals between a first node 110 and a secondnode 120 within a wireless communication network 100.

A general concept of the present method and arrangement is to combinethe previously discussed criteria of transmitted number of data unitssuch as e.g. PDUs and the number of data bytes of the transmitted dataunits into a single mechanism in order to trig a poll, e.g. a requestfor a status report from the second node 120.

210

The first node 110 may comprise a data unit counter and a bytes counter.The first node 110 may begin a transmission session by initialising adata unit counter and a bytes counter to zero in a first step 210.

220

The first node 110 then transmits data units e.g. to be received by thesecond node 120. For each transmitted data unit, the data unit counteris accordingly increased and for each byte sent, the bytes counter isincreased.

230

A comparison is then made, concerning if the data unit counter hasreached or exceeded a first threshold limit value. Also, a furthercomparison is made concerning if the byte counter has reached orexceeded a second threshold limit value.

The first and the second threshold limit values may be predetermined orset e.g. depending of the type of data that is sent, as some types ofdata may be more sensitive to loss than other types of data. The firstand the second threshold limit values may be set by the network 100,e.g. by the Radio Resource Control (RRC) protocol. In LTE the thresholdsare configured by RRC. In WCDMA/HSPA the thresholds may also beconfigured by RRC which for HSPA is terminated in the RNC 130 and theuser equipment. For LTE the RRC is terminated in the eNodeB and the userequipment.

240

If any of the first or the second threshold limit values is reached orexceeded, a poll is triggered. Thus a poll is generated at the firstnode 110 and sent to the second node 120. Also, the data unit counterand the Byte counter are reset after sending the poll, according to someembodiments.

250

The second node 120, when receiving the poll, generates a status reportconcerning the received data.

260

The generated status report is sent from the second node 120 to thefirst node 110.

The threshold limit values concerning transmitted data units andtransmitted bytes may be referred to as PDU_Threshold and ByteThreshold,respectively.

The threshold limit values PDU_Threshold or ByteThreshold may be set toany arbitrary value. In some particular embodiments, any of the first orthe second threshold limit values may be set to a value representinginfinite threshold value or mechanism disabled. The present mechanismthus, according to some embodiments, may operate as a pure byte basedsolution, in case the PDU_Threshold is set to an infinite thresholdvalue. Alternatively, the present mechanism may operate as a purecounter based solution, in case the ByteThreshold is set to an infinitethreshold value.

The described method may be denoted, in a compressed way of writing:

Initialise PDU_Counter and ByteCounter to their starting values;[transmit data]; IF (PDU_Counter≧PDU_Threshold) OR(ByteCounter≧ByteThreshold) THEN - Trigger a poll; - Reset PDU_CounterAND ByteCounter; END IF.

The benefit with the above described procedure is that stalling due toboth sequence number limitation and memory limitation can be avoided byhelp of one single mechanism. By combining the two criteria into onemechanism it may be avoided that a poll is unnecessarily sent when afirst criterion is fulfilled in situations when such a poll has alreadyrecently been triggered due to the other, second criterion.

In order to clarify and further illustrate the present method, yet anexample is discussed below. However, it is to be noted that this is anon limiting example only, not intended to limit the scope of thepresent method in any way, which scope is limited by the independentclaims only.

According to some embodiments, the configured parameter byte thresholdlimit value, ByteThreshold, may be scaled in accordance with the numberof configured or active bearers. Thus, according to some embodiments thenetwork 100 may configure the byte threshold limit value ByteThresholdand polling may be triggered when the byte threshold limit value pernumber of radio bearers have been transmitted.

Thus, expressed in a compressed way of writing:

Initialise PDU_Counter and ByteCounter to their starting values;[transmit data]; determine the number of radio bearers; IF (PDU_Counter≧ PDU_Threshold) OR (ByteCounter ≧ (ByteThreshold/ number_of_bearers))THEN - Trigger a poll; - Reset PDU_Counter AND ByteCounter; END IF.

This scaling which also takes the number of radio bearers into account,compensates for the fact that memory may be occupied by outstanding dataunits e.g. PDUs on each radio bearer.

Although the present invention has been described for implementation inan evolved UTRAN (E-UTRAN) environment, similar principles may also beapplicable for UTRAN when flexible data unit sizes are introduced e.g.flexible RLC PDU sizes.

An advantage of the present methods and arrangements is that theyoperate on both bytes and data units and avoids stalling due to bothsequence number limitation and memory limitation. This is achieved by asingle mechanism which coordinates the polling by two criteria leadingto an efficient polling.

FIG. 3 is a flow chart illustrating embodiments of method steps 301-312performed in a first node 110. The method aims at requesting a statusreport from a second node 120. The action: “To request a status report”may also be referred to as “to send a poll”, or “setting a poll bit”. Inthe following text, the expression: “To request a status report” willconsistently be used for clarity reasons, but it is to be understoodthat several other expressions bearing the same meaning might be usedinstead, e.g. “to send a poll”, or “setting a poll bit”. The first node110 and the second node 120 are comprised within a wirelesscommunication network 100. The status report comprising positive and/ornegative acknowledgement of data sent from the first node 110 to bereceived by the second node 120.

As previously discussed, the first node 110 may be a base station andthe second node 120 may be a mobile station.

However, any, some or even all of the method steps 301-312 performed inthe first node 110, when the first node is represented by a basestation, may be distributed between the base station and the controlnode 130. The control node 130 may be e.g. a Radio Network Controller,RNC. Thus any, some or all of the method steps 301-312 according toembodiments of the present method may be performed entirely or at leastto some extent in the control node 130.

However, according to some embodiments, the first node 110 may be amobile station such as e.g. a mobile phone and the second node 120 maybe a base station.

To appropriately request a status report from the second node 120, themethod may comprise a number of method steps 301-312. It is however tobe noted that some of the described method steps are optional and onlycomprised within some embodiments. Further, it is to be noted that themethod steps 301-312 may be performed in any arbitrary chronologicalorder and that some of them, e.g. step 304 and step 305, or even allsteps may be performed simultaneously or in an altered, arbitrarilyrearranged, decomposed or even completely reversed chronological order.The method may comprise the following steps:

Step 301

This step is optional and may only be comprised within some embodimentsof the present method. The first counter 421 may be initialised.

According to some embodiments, the first counter 421 may be initialisedto zero and adapted to count the number of transmitted data units. Thusthe first counter 421 may be incremented according to the transmittednumber of data units, until a first predetermined value is reached orexceeded.

However, the first counter 421 may according to some other embodimentsbe initialised to the first predetermined value. The first counter 421may then be decreased according to the transmitted number of data units,until zero is reached or fallen below.

Step 302

This step is optional and may only be comprised within some embodimentsof the present method. The second counter 422 may be initialised.

According to some embodiments, the second counter 422 may be initialisedto zero and adapted to count the number of transmitted data bytes.According to those embodiments, the second counter 422 may beincremented according to the transmitted number of data bytes, until asecond predetermined value is reached or exceeded.

According to other embodiments, the second counter 422 may beinitialised to the second predetermined value. The second counter 422may then be decreased according to the transmitted number of data bytes,until zero is reached or fallen below.

Step 303

This step is optional. In this step, the number of configured or activeradio bearers may be obtained.

The configured radio bearers are given by the Radio Resource Control,RRC. The active radio bearers, i.e. the radio bearers where there istraffic could be determined by the sending node itself based on thetransmitted data.

Step 304

This step is optional and may only be comprised within some embodimentsof the present method. A first predefined value related to the number oftransmitted data units may be obtained. The first predefined value maybe a threshold limit value defining the maximum numbers of data unitsthat may be transmitted before a request for a status report is sent tothe second node. The data units may be e.g. Protocol Data Units, PDUs,according to some embodiments. The first predefined value may beconfigured by, and obtained from, a higher layer, e.g. the RadioResource Control, RRC.

Step 305

This step is optional and may only be comprised within some embodimentsof the present method. A second predefined value related to the numberof transmitted data bytes, may be obtained. The second predefined valuemay be a threshold limit value defining the maximum amount of data bytesthat may be transmitted before a request for a status report is sent tothe second node. The second predefined value may be configured by, andobtained from, a higher layer, e.g. the Radio Resource Control, RRC.

According to some optional embodiments, the step of obtaining the secondpredefined value comprises obtaining a parameter value representing abytes threshold limit value and dividing that parameter value with theobtained number of configured or active radio bearers.

Step 306

The first node 110 transmits data units, to be received by the secondnode 120.

Step 307

The number of transmitted data units and the number of transmitted databytes are counted, as data is sent to be received by the second node120.

The first node 110 may according to some embodiments comprise a firstcounter 421 configured to count the number of transmitted data units.According to some embodiments, the first node 110 may comprise a secondcounter 422. The second counter 422 may be configured to count thenumber of transmitted data bytes.

The step of counting may optionally comprise to adjust the first counter421 according to the amount of data units transmitted to the second node120. Further, the second counter 422 may be adjusted according to theamount of data bytes transmitted to the second node 120.

The step of counting may optionally, according to some embodiments,comprise to increment the first counter 421 according to the amount ofdata units transmitted to the second node 120. Further, the secondcounter 422 may be incremented according to the amount of data bytestransmitted to the second node 120.

The step of counting may according to some optional further embodiments,comprise to decrease the first counter 421 according to the amount ofdata units transmitted to the second node 120. Further, the secondcounter 422 may be decreased according to the amount of data bytestransmitted to the second node 120.

Step 308

This step is optional and may only be comprised within some embodimentsof the present method. The value of the first counter 421 may becompared with the first predefined value if the first counter 421 hasbeen incremented according to the transmitted amount of data units. Thefirst predefined value may be a threshold limit value defining themaximum numbers of data units that may be transmitted before a requestfor a status report is sent to the second node.

According to some embodiments, first counter 421 may be compared withzero, if the first counter 421 has been decreased according to thetransmitted amount of data units. Thus according to some optionalembodiments, wherein the first counter 421 has been initialised and/orreset to the first predetermined value and wherein the first counter 421has been decreased according to the amount of data units transmitted tothe second node 120, the value of the first counter 421 may be comparedwith zero. The count down from the first predefined value to zero maythen correspond to the maximum numbers of data units that may betransmitted before a request for a status report is sent to the secondnode.

According to some embodiments, the absolute value of the first counter421, i.e. the magnitude of the first counter 421 may be compared withthe absolute value i.e. the magnitude of the first predefined value.

Step 309

This step is optional and may only be comprised within some embodimentsof the present method. The value of the second counter 422 may becompared with the second predefined value if the second counter 422 hasbeen incremented according to the transmitted amount of data bytes. Thesecond predefined value may be a threshold limit value defining themaximum amount of data bytes that may be transmitted before a is requestfor a status report is sent to the second node.

According to some embodiments, second counter 422 may be compared withzero, if the second counter 422 has been decreased according to thetransmitted amount of data bytes. Thus, according to some optionalembodiments, wherein the second counter 422 has been initialised and/orreset to the first predetermined value and wherein the second counter422 has been decreased according to the amount of data bytes transmittedto the second node 120, the value of the second counter 422 may becompared with zero. The count down from the second predefined value tozero may then correspond to the maximum numbers of data bytes that maybe transmitted before a request for a status report is sent to thesecond node.

According to some embodiments, the absolute value of the second counter422, i.e. the magnitude of the second counter 422 may be compared withthe absolute value i.e. the magnitude of the second predefined value.

Step 310

A status report is requested from the second node 120 if the countednumber of transmitted data units or the counted number of transmitteddata bytes exceeds predefined values.

According to some optional embodiments, a status report may be requestedfrom the second node 120 if the maximum numbers of data units that maybe transmitted is reached or exceeded by the first counter 421 or if themaximum numbers of data bytes that may be transmitted is reached orexceeded by the second counter 422.

According to some further optional embodiments, a status report may berequested from the second node 120 if the first predefined value isreached or exceeded by the first counter 421 or if the second predefinedvalue is reached or exceeded by the second counter 422.

According to yet some further optional some embodiments, wherein thefirst counter 421 and/or the second counter 422 has been initialisedand/or reset to the first predefined value and/or the second predefinedvalue respectively, a status report may be requested from the secondnode 120 if zero is reached or fallen below by the first counter 421 orif is zero is reached or fallen below by the second counter 422.

Step 311

This step is optional and may only be comprised within some embodimentsof the present method. The first counter 421 may be reset to zero.According to yet some optional embodiments, the first counter 421 may bereset to the first predetermined value.

Optionally, the first counter 421 may be reset when the first predefinedvalue is reached or exceeded by the first counter 421 or if the secondpredefined value is reached or exceeded by the second counter 422.

According to some further optional embodiments, the first counter 421may be reset when zero is reached or fallen below by the first counter421 or if zero is reached or fallen below by the second counter 422.

According to some embodiments, the first counter 421 may be reset when arequest for a status report is sent to the second node 120, or when apoll bit is set to 1.

Step 312

This step is optional and may only be comprised within some embodimentsof the present method. The second counter 422 may be reset to zero.According to yet some optional embodiments, the second counter 422 maybe reset to the second predetermined value.

Optionally, the second counter 422 may be reset when the firstpredefined value is reached or exceeded by the first counter 421 or whenthe second predefined value is reached or exceeded by the second counter422.

According to some further optional embodiments, the second counter 422may be reset when zero is reached or fallen below by the first counter421 or if zero is reached or fallen below by the second counter 422.

According to some embodiments, the second counter 422 may be reset whena request for a status report is sent to the second node 120, or when apoll bit is set to 1.

FIG. 4 is a block diagram illustrating embodiments of an arrangement 400situated in the first node 110. The arrangement 400 is configured toperform the method steps 301-312 for requesting a status report from thesecond node 120. The first node 110 and the second node 120 are bothcomprised within a wireless communication network 100. The status reportcomprises positive and/or negative acknowledgement of data sent from thefirst node 110 to be received by the second node 120. The first node110, wherein the present arrangement 400 is comprised may be representedby a user equipment such as e.g. a mobile phone, according to someembodiments. However, according to some embodiments, the first node 110may be represented by a base station such as e.g. an evolved NodeB(eNodeB). According to other embodiments, the first node 110 may berepresented by a control node 130 such as e.g. a Radio NetworkController (RNC).

For the sake of clarity, any internal electronics of the arrangement400, not completely necessary for performing the present method has beenomitted from FIG. 4.

The arrangement 400 comprises a transmitter 406. The transmitter 406 isadapted to transmit a sequence of data units or data unit segments, dataunits, to be received by the second node 120. The arrangement 400 alsocomprises a counting mechanism 407, adapted to count the number oftransmitted data units and the number of transmitted data bytes. Thecounting mechanism 407 may according to some embodiments comprise afirst counter 421. The optional first counter 421 may be adapted tocount the number of transmitted data units. The counting mechanism 407may optionally comprise a second counter 422. The second counter 422 maybe adapted to count the number of transmitted data bytes. Further, thearrangement 400 comprises a requesting unit 410. The requesting unit 410is adapted to request a status report from the second node 120. Thestatus report is requested if the counted number of transmitted dataunits or the counted number of transmitted data bytes exceeds predefinedvalues. The data units may be e.g. PDUs.

The requesting unit 410 may, according to some optional embodiments, beadapted to send a request for a status report from the second node 120if the first predefined value is reached or exceeded by the firstcounter 421 or if the second predefined value is reached or exceeded bythe second counter 422.

The counting mechanism 407, comprised within the arrangement 400 mayaccording to some embodiments further comprise a first counter 421. Thefirst counter 421 may be configured to count the number of transmitteddata units. The counting mechanism 407 may further comprise a secondcounter 422. The second counter 422 may be configured to count thenumber of transmitted data bytes.

The arrangement 400 may according to some embodiments comprise a firstobtaining unit 404. The optional first obtaining unit 404 may be adaptedto obtain a first predefined value related to the number of transmitteddata units.

The arrangement 400 may according to some embodiments comprise a secondobtaining unit 405. The optional second obtaining unit 405 may beadapted to obtain a second predefined value related to the number oftransmitted data bytes. According to yet some embodiments, the secondobtaining unit 405 may be further adapted to obtain a parameter valuerepresenting a bytes threshold limit value and dividing that parametervalue with the obtained number of configured or active radio bearers.

According to some embodiments, the arrangement 400 may comprise a firstcomparison unit 408. The first comparison unit 408 may be adapted tocompare the value of the first counter 421 with the first predefinedvalue. The first predefined value is related to the number oftransmitted data units and may represent a maximum threshold limitvalue.

According to some embodiments, the arrangement 400 may comprise a secondcomparison unit 409. The second comparison unit 409 may be adapted tocompare the value of the second counter 422 with the second predefinedvalue. The second predefined value is related to the number oftransmitted data bytes and may represent a maximum threshold limitvalue.

As previously discussed, the first predefined value and the secondpredefined value are configured by and obtained from a higher layer,e.g. the Radio Resource Control, RRC.

The arrangement 400 may optionally, according to some embodiments,comprise a first initialising unit 401. The first initialising unit 401may be adapted to initialise the first counter 421 to zero. According tosome embodiments, the first initialising unit 401 may be adapted toinitialise the first counter 421 to the first predetermined value.

According to some embodiments, the arrangement 400 may comprise a secondinitialising unit 402. The second initialising unit 402 may be adaptedto initialise the second counter 422 to zero. According to someembodiments, the second initialising unit 402 may be adapted toinitialise the second counter 422 to the second predetermined value.

Further, according to some embodiments of the present arrangement 400, afirst resetting unit 411 may be comprised. The first resetting unit 411may be adapted to reset the first counter 421 to zero. According to someembodiments, the first resetting unit 411 may be adapted to reset thefirst counter 421 to the first predetermined value.

Some embodiments of the present arrangement 400 may comprise a secondresetting unit 412. The second resetting unit 412 may be adapted toreset the second counter 422 to zero. According to some embodiments, thesecond resetting unit 412 may be adapted to reset the second counter 422to the second predetermined value.

The arrangement 400 may according to some embodiments comprise a thirdobtaining unit 403. The third obtaining unit 403 may be adapted toobtain the number of configured or active radio bearers.

The arrangement 400 may according to some embodiments comprise aprocessing unit 420. The processing unit 420 may be represented by e.g.a Central Processing Unit (CPU), a processor, a microprocessor, orprocessing logic that may interpret and execute instructions. Theprocessing unit 420 may perform all data processing functions forinputting, outputting, and processing of data including data bufferingand device control functions, such as call processing control, userinterface control, or the like.

It is to be noted that the described units 401-422 comprised within thearrangement 400 are to be regarded as separate logical entities but notwith necessity separate physical entities. Any, some or all of the units401-422 may be comprised or co-arranged within the same physical unit.However, in order to facilitate the understanding of the functionalityof the arrangement 400, the comprised units 401-422 are illustrated asseparate physical units in FIG. 4.

Some Particular Embodiments

The method in the first node 110 for requesting a status report from thesecond node 120, according to the present method may be implementedthrough one or more processors 420 in the first node 110, together withcomputer program code for performing the functions of the method. Theprogram code mentioned above may also be provided as a computer programproduct, for instance in the form of a data carrier carrying computerprogram code for performing the method according to the presentinvention when being loaded into the processing unit 420. The datacarrier may be a CD ROM disc, a memory stick, or any other appropriatemedium such as a disk or tape that can hold machine readable data. Thecomputer program code can furthermore be provided as pure program codeon a server and downloaded to the first node 110 remotely.

Thus a computer program comprising instruction sets for performing themethod according to at least some of the method steps 300-312 may beused for implementing the previously described method.

As will be appreciated by one of skill in the art, the present inventionmay be embodied as an arrangement 400 within a first node 110, a methodor a computer program product.

Accordingly, the present invention may take the form of an entirelyhardware embodiment, a software embodiment or an embodiment combiningsoftware and hardware aspects all generally referred to herein as a“circuit” or “module.” Furthermore, the present invention may take theform of a computer program product on a computer-usable storage mediumhaving computer-usable program code embodied in the medium. Any suitablecomputer readable medium may be utilized including hard disks, CD-ROMs,optical storage devices, a transmission media such as those supportingthe Internet or an intranet, or magnetic storage devices.

Computer program code for carrying out operations of the presentinvention may be written in any arbitrary object oriented programminglanguage such as Java®, Smalltalk or C++. However, the computer programcode for carrying out the steps of the present method may also bewritten in any conventional procedural programming languages, such asthe “C” programming language and/or a lower level assembler language.The program code may execute entirely on the arrangement 400, partly onthe arrangement 400, as a stand-alone software package, partly on thearrangement 400 and partly on a remote computing device or entirely onthe remote computing device. In the latter scenario, the remotecomputing device may be connected to the arrangement 400 through a localarea network (LAN) or a wide area network (WAN), or the connection maybe made to an external computer, for example, through the Internet usinge.g. an Internet Service Provider.

Furthermore, the present method is described in part above withreference to flowchart illustrations in FIG. 2 and FIG. 3 and/or blockdiagrams of arrangements, methods, and computer program productsaccording to embodiments of the invention. It will be understood thateach block of the flowchart illustrations and/or block diagrams, andcombinations of blocks in the flowchart illustrations and/or blockdiagrams, may be implemented by computer program instructions. Thesecomputer program instructions may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks in FIG. 2 or FIG. 3.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

The terminology used in the detailed description of the particularexemplary embodiments illustrated in the accompanying drawings is notintended to be limiting of the invention.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless expressly stated otherwise. Itwill be further understood that the terms “includes,” “comprises,”“including” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. It will be understood thatwhen an element is referred to as being “connected” or “coupled” toanother element, it can be directly connected or coupled to the otherelement or intervening elements may be present. Furthermore, “connected”or “coupled” as used herein may include wirelessly connected or coupled.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

1. A method for requesting a status report from a node in a wirelesscommunication network, the status report comprising at least one ofpositive and negative acknowledgement of data sent from the first nodeto be received by the second node, the method comprising: transmitting asequence of data units or data unit segments from a first network nodeto a second network node; decreasing a first counter based on a numberof data units transmitted; decreasing a second counter based on a numberof bytes of data transmitted; determining whether a count of the firstcounter is less than or equal to a first threshold; determining whethera count of the second counter is less than or equal to a secondthreshold; and in response to determining that either the count of thefirst counter is less than or equal to the first threshold or the countof the second counter is less than or equal to the second threshold:requesting a status report from the second node; and resetting both thefirst counter to a first predefined value and the second counter to asecond predefined value.
 2. The method of claim 1, wherein the firstthreshold equals zero and the second threshold equals zero.
 3. Themethod of claim 1, further comprising obtaining the first predefinedvalue and the second predefined value from a higher layer.
 4. The methodof claim 3, wherein the higher layer comprises a Radio Resource Control(RRC) layer.
 5. The method of claim 1, further comprising: obtaining anumber of configured or active radio bearers; and obtaining the secondpredefined value by obtaining a parameter value representing a bytesthreshold limit value and dividing that parameter value by the obtainednumber of configured or active radio bearers.
 6. The method of claim 1,wherein the first network node comprises a user equipment.
 7. The methodof claim 1, wherein the first network node comprises a base station, aRadio Network Controller (RNC), or an evolved NodeB.
 8. An apparatus forrequesting a status report from a node of a wireless communicationnetwork, the status report comprising at least one of positive andnegative acknowledgement of data to be received by the network node, theapparatus comprising: a transmitter, adapted to transmit a sequence ofdata units or data unit segments to be received by the network node; acounting mechanism, adapted to: decrease a first counter based on anumber of data units transmitted; decrease a second counter based on anumber of bytes of data transmitted; determine whether a count of thefirst counter is less than or equal to a first threshold; and determinewhether a count of the second counter is less than or equal to a secondthreshold; a first comparison unit, adapted to compare a count of thefirst counter to the first threshold; a second comparison unit, adaptedto compare a count of the second counter to the second threshold; arequesting unit, adapted to request a status report from the second nodeif-either the count of the first counter is less than or equal to thefirst threshold or the count of the second counter is less than or equalto the second threshold; a first resetting unit, adapted to reset thefirst counter to a first predefined value if either the count of thefirst counter is less than or equal to the first threshold or the countof the second counter is less than or equal to the second threshold, anda second resetting unit, adapted to reset the second counter to a secondpredefined value if either the count of the first counter is less thanor equal to the first threshold or the count of the second counter isless than or equal to the second threshold.
 9. The apparatus of claim 8,wherein the first threshold equals zero and the second threshold equalszero.
 10. The apparatus of claim 8, wherein: the first resetting unit isfurther adapted to obtain the first predefined value from a higherlayer; and the second resetting unit is further adapted to obtain thesecond predefined value from the higher layer.
 11. The apparatus ofclaim 10, wherein the higher layer comprises a Radio Resource Control(RRC) layer.
 12. The apparatus of claim 8, wherein the second resettingunit is further adapted to: obtain a number of configured or activeradio bearers; and obtain the second predefined value by obtaining aparameter value representing a bytes threshold limit value and dividingthat parameter value by the obtained number of configured or activeradio bearers.
 13. The apparatus of claim 8, wherein the apparatuscomprises a user equipment.
 14. The apparatus of claim 8, wherein theapparatus comprises a base station, a Radio Network Controller (RNC), oran evolved NodeB.